Universe re-created in computer simulation

Most detailed model of cosmos reproduces distribution of galaxies

VIRTUAL UNIVERSE In a snapshot from the Illustris computer simulation of the universe, galaxies (pink) cluster along filaments of dark matter (blue). Shown is the most massive cluster in the simulation, in a volume of space roughly 70 million light-years across horizontally. Gas bubbles (orange) rapidly burst from the centers of galaxies, where supermassive black holes drive intergalactic winds that stir up gas for hundreds of thousands of light-years.

“If you wish to make an apple pie from scratch,” said Carl Sagan, “you must first invent the universe.” A new simulation of the evolution of the universe, called the Illustris Project, is a start. Led by Mark Vogelsberger, an astrophysicist at MIT, Illustris is the most detailed and comprehensive simulation of the universe to date and produces a cosmos that looks similar to today’s.

“The only way we can learn about the universe is to observe it through telescopes,” says Vogelsberger. And the way to test ideas about its evolution, he adds, is by doing simulations. One of the simulation’s insights, reported in the May 8 Nature, is the role that supermassive black holes must have played in shaping galaxies. As the behemoths swallow gas, they are known to belch out energetic gas bubbles that span hundreds of thousands of light-years. Without these eruptions, the universe would look much different; galaxies would be larger, for example.

Illustris tracks 12 billion grid cells in a cube 350 million light-years on a side as it evolves from 12 million years after the Big Bang to the present. To run the simulation, the researchers required 19 million CPU hours, or the equivalent of more than 2,000 years on one processor.

VIRTUAL UNIVERSE Watch the universe evolve, from 12 million years after the Big Bang to the present, in a video from the most detailed simulation of the cosmos to date. The movie follows a cube of space about 30 million light-years across as wisps of dark matter grow to become the stars, galaxies and superclusters seen today.Courtesy of: Illustris Collaboration; produced by Ashley Yeager